MVVM vs. MVI: Choosing the Right Architecture for Your Mobile App in 2025

Building a successful mobile application is like constructing a skyscraper. You can have a stunning facade and brilliant features, but without a solid foundation—a robust architecture—it will eventually crumble under its own weight. Choosing the right architectural pattern is one of the most critical decisions you'll make, impacting scalability, testability, and your team's sanity.

For years, MVVM (Model-View-ViewModel) has been the go-to pattern for many, championed by Google and widely adopted in the Android community. But a powerful challenger has gained significant traction, especially with the rise of declarative UI frameworks: MVI (Model-View-Intent).

So, which one should you bet on for your next project in 2025? This isn't about finding a single "best" pattern, but about understanding the trade-offs. Let's break down MVVM and MVI to help you make an informed architectural decision.

The Established Champion: Understanding MVVM

MVVM is a battle-tested pattern designed to separate the UI (the View) from the business logic and data (the Model). The star of the show is the ViewModel, which acts as a mediator.

• Model: This is your data layer. It handles data retrieval from APIs or a local database and contains the core business logic. It knows nothing about the UI.
• View: This is the UI layer (e.g., your Activities/Fragments and Jetpack Compose Composables, or your SwiftUI Views). Its job is to display data and capture user input. It should be as "dumb" as possible.
• ViewModel: The bridge between the Model and the View. It holds and exposes UI-related data that the View can observe. It receives events from the View, processes them (often using the Model), and updates its state, which the View then automatically reflects.

The core mechanism of MVVM is data binding or observation. The View observes state holders (like StateFlow in Kotlin or @Published properties in Swift) exposed by the ViewModel. When the data in the ViewModel changes, the View is notified and updates itself.

Strengths of MVVM

• Maturity and Community Support: MVVM is well-documented, and you'll find countless tutorials, libraries, and solutions to common problems.
• Decoupled and Testable: By separating UI from logic, ViewModels can be unit-tested without needing the Android framework or UI components.
• Approachable: The concepts are relatively straightforward, making it easier for new developers to get up to speed.

Weaknesses of MVVM

• State Management Complexity: In complex screens, a single ViewModel might have numerous mutable state variables (var user, var isLoading, var error, etc.). Managing these many states and their transitions can become unwieldy.
• "Event" Ambiguity: How do you handle one-off events like showing a Toast or navigating to another screen? This has led to various solutions like "SingleLiveEvent" patterns, which can feel like workarounds.
• Bi-directional Data Flow: While the state flows from the ViewModel to the View, the View also sends commands to the ViewModel. In complex scenarios, it can sometimes be difficult to trace exactly why a certain state change occurred.

The Unidirectional Challenger: Understanding MVI

MVI is inspired by frontend web frameworks like Redux and is built around the concept of a unidirectional data flow. This creates a predictable, cyclical, and traceable application state.

The components are slightly different:

• Model: In MVI, the "Model" often refers to the State. It's typically a single, immutable data class representing the entire state of a screen (e.g., data class ProfileState(val user: User?, val isLoading: Boolean)).
• View: The UI layer, same as in MVVM. However, its primary jobs are to render the State and translate user actions into Intents.
• Intent: Not to be confused with Android's Intent class. Here, an Intent represents a user's intention to do something (e.g., RefreshDataIntent, UserNameChangedIntent).

The MVI loop is strict and predictable:

1. The View renders a single State object.
2. A user performs an action, and the View translates this into an Intent and fires it off.
3. The Intent is processed by a business logic component (like a ViewModel).
4. This logic performs a task and produces a new, immutable State.
5. The View receives the new State and re-renders itself. The loop is complete.

Strengths of MVI

• Single Source of Truth: With only one state object per screen, there's no ambiguity about the UI's current condition. This eliminates a whole class of bugs related to inconsistent state.
• Predictability and Debuggability: Since data flows in one direction, you can easily log the Intents and the resulting State changes. This makes debugging a breeze—you have a clear timeline of what happened and why.
• Excellent for Complex UI: MVI shines in screens with many moving parts and complex user interactions because it forces you to model every possibility as a distinct state.

Weaknesses of MVI

• Boilerplate: MVI can require more initial setup. You need to define classes/objects for every Intent and a single comprehensive State data class, which can feel verbose for simple screens.
• Steeper Learning Curve: The concepts of immutability, unidirectional flow, and reactive programming (which MVI heavily relies on) can be challenging for developers new to the paradigm.
• Potential Performance Overhead: Creating a new state object for every single change can, in theory, impact performance. However, modern languages and diffing algorithms in UI toolkits like Compose and SwiftUI make this a non-issue in almost all cases.

Head-to-Head: MVVM vs. MVI

So, Which Architecture Should You Choose?

There is no one-size-fits-all answer, but here is our advice at Norseson Labs for making the right choice in 2025:

Choose MVVM if...

• Your team is more familiar with traditional object-oriented patterns.
• Your application consists of many simple "read-and-display" screens.
• Speed of initial development is the top priority, and you want to leverage the vast ecosystem of existing MVVM resources.

Choose MVI if...

• Your app has screens with complex, interdependent states (think a video editor, a complex settings screen, or a real-time dashboard).
• Long-term maintainability and testability are your primary concerns.
• Your team is comfortable with or eager to learn reactive programming principles.
• You want an architecture that perfectly complements the declarative nature of Jetpack Compose and SwiftUI.

Conclusion: An Evolution, Not a Revolution

MVI is not here to kill MVVM. Rather, it represents an evolution in how we think about state management in a declarative UI world. The shift towards unidirectional data flow is a direct response to the increasing complexity of modern user interfaces.

The best architecture is the one that empowers your team to build a high-quality, maintainable product efficiently. For many projects, a well-structured MVVM is a perfectly pragmatic and powerful choice. For others, the strict discipline of MVI provides the robust foundation needed to tackle complexity with confidence.

At Norseson Labs, we don't commit to a single pattern. We analyze the specific challenges of each project and choose the architecture that will best serve its long-term goals. Whether it's the reliability of MVVM or the predictability of MVI, we build on a foundation designed to last.